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Subject: Re: AOA issue
From: "Greenbacks, UnLtd." <N4ZQ@verizon.net>
Date: Tue, 12 Nov 2013 08:54:17 -0500
Cc: List Lancair Mailing <lml@lancaironline.net>
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To: Pastusek Robert <rpastusek@htii.com>

Hi Bob,

I had never before powered up the AOA while in flight so had never seen =
those error messages.
The pressure port lines have quick disconnect fittings thanks to Bill H, =
so I'll apply some pressure
at the fitting and blow toward the wing tip. Will check for loose =
connections today.

Angier

Begin forwarded message:

> From: Robert R Pastusek <rpastusek@htii.com>
> Date: November 12, 2013 12:48:53 AM EST
> To: "Greenbacks, UnLtd." <N4ZQ@verizon.net>
> Subject: FW: [LML] Re: AOA issue
>=20
> Angier,
>=20
> This and the earlier messages accurately describe how the AOA =
works/self-tests. You'll always get these error messages if you power up =
the unit in flight, and can get them on the ground in a strong wind as =
the sensor comparisons for test will fail under windy conditions. =
Dimming is a sequential function of grounding one of the leads. One =
grounding causes it to go dim; the next bright, and so on. A loose =
connection, or intermittent short can cause this, as well as an =
"un-commanded" self-test. Ditto for an interruption of input power. =
These are far more likely than a malfunction of the system.=20
>=20
> BE SURE you don't apply compressed air to the AOA sensors themselves, =
and I'd strongly recommend against even blowing into the lines when they =
are attached to the sensors. The pressure differential they are =
measuring is in millibars/inches of water...in other words, very small. =
They can be easily damaged by such action.
>=20
> Bob
>=20
> -----Original Message-----
> From: Lancair Mailing List [mailto:lml@lancaironline.net] On Behalf Of =
John Cooper
> Sent: Monday, November 11, 2013 7:33 AM
> To: lml@lancaironline.net
> Subject: [LML] Re: AOA issue
>=20
> The AoA display getting dim sounds like a separate problem, but the =
E11 and E33 may have been due to water in the sense lines, or perhaps a =
loose ground wire at the red and black pushbuttons. The E33 just means =
that some other error was reported and, (from the manual) the E11 means:
>> Reasonableness ramp check of the wing
>> differential pressure transducer is not within acceptable limits. =
This=20
>> may be due to wind or might be due to damage of the differential=20
>> pressure transducer. If the system re-tests OK in a hangar, assume =
the=20
>> problem was due to wind.
>> If the error persists, a re-calibration of the AOA may fix the=20
>> problem. If the test function was activated during flight, this error=20=

>> message is expected and normal.
> I'd remove the sense lines at the CPU and *gently* blow them out just =
to be sure, but is it possible that you may have inadvertently touched =
the black and red push buttons? As you know, the black is the dimmer =
button and the red is the test button which would account for both your =
problems. Is it possible that ground wire to those two buttons is loose?=20=

> I'd closely inspect the wiring to those two push buttons.
>=20
>=20
> --
> For archives and unsub =
http://mail.lancaironline.net:81/lists/lml/List.html